Avapritinib Versus Regorafenib in Locally Advanced Unresectable or Metastatic GI Stromal Tumor: A Randomized, Open-Label Phase III Study.

Abstract

PURPOSE:

Primary or secondary mutations in KIT or platelet-derived growth factor receptor alpha (PDGFRA) underlie tyrosine kinase inhibitor resistance in most GI stromal tumors (GISTs). Avapritinib selectively and potently inhibits KIT- and PDGFRA-mutant kinases. In the phase I NAVIGATOR study (NCT02508532), avapritinib showed clinical activity against PDGFRA D842V-mutant and later-line KIT-mutant GIST. VOYAGER (NCT03465722), a phase III study, evaluated efficacy and safety of avapritinib versus regorafenib as third-line or later treatment in patients with unresectable or metastatic GIST.

PATIENTS AND METHODS:

VOYAGER randomly assigned patients 1:1 to avapritinib 300 mg once daily (4 weeks continuously) or regorafenib 160 mg once daily (3 weeks on and 1 week off). Primary end point was progression-free survival (PFS) by central radiology per RECIST version 1.1 modified for GIST. Secondary end points included objective response rate, overall survival, safety, disease control rate, and duration of response. Regorafenib to avapritinib crossover was permitted upon centrally confirmed disease progression.

RESULTS:

Four hundred seventy-six patients were randomly assigned (avapritinib, n = 240; regorafenib, n = 236). Median PFS was not statistically different between avapritinib and regorafenib (hazard ratio, 1.25; 95% CI, 0.99 to 1.57; 4.2 v 5.6 months; P = .055). Overall survival data were immature at cutoff. Objective response rates were 17.1% and 7.2%, with durations of responses of 7.6 and 9.4 months for avapritinib and regorafenib; disease control rates were 41.7% (95% CI, 35.4 to 48.2) and 46.2% (95% CI, 39.7 to 52.8). Treatment-related adverse events (any grade, grade ≥ 3) were similar for avapritinib (92.5% and 55.2%) and regorafenib (96.2% and 57.7%).

CONCLUSION:

Primary end point was not met. There was no significant difference in median PFS between avapritinib and regorafenib in patients with molecularly unselected, late-line GIST.

• Authors: Yoon-Koo Kang, Suzanne George, Robin L Jones, Piotr Rutkowski, Lin Shen, Olivier Mir, Shreyaskumar Patel, Yongjian Zhou, Margaret von Mehren, Peter Hohenberger, Victor Villalobos, Mehdi Brahmi, William D Tap, Jonathan Trent, Maria A Pantaleo, Patrick Schöffski, Kevin He, Paggy Hew, Kate Newberry, Maria Roche, Michael C Heinrich, Sebastian Bauer
• Journal: Journal of clinical oncology : official journal of the American Society of Clinical Oncology (J Clin Oncol) Vol. 39 Issue 28 Pg. 3128-3139 (10 01 2021) ISSN: 1527-7755 [Electronic] United States
• PMID: 34343033 (Publication Type: Clinical Trial, Phase III, Comparative Study, Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Antineoplastic Agents
• Phenylurea Compounds
• Protein Kinase Inhibitors
• Pyrazoles
• Pyridines
• Pyrroles
• Triazines
• regorafenib
• avapritinib
• KIT protein, human
• Proto-Oncogene Proteins c-kit
• Receptor, Platelet-Derived Growth Factor alpha

Topics

• Adult
• Aged
• Aged, 80 and over
• Antineoplastic Agents (administration & dosage, adverse effects)
• Asia
• Australia
• Disease Progression
• Drug Administration Schedule
• Europe
• Female
• Gastrointestinal Neoplasms (drug therapy, genetics, mortality, pathology)
• Gastrointestinal Stromal Tumors (drug therapy, genetics, mortality, secondary)
• Humans
• Male
• Middle Aged
• Mutation
• North America
• Phenylurea Compounds (administration & dosage, adverse effects)
• Progression-Free Survival
• Protein Kinase Inhibitors (administration & dosage, adverse effects)
• Proto-Oncogene Proteins c-kit (antagonists & inhibitors, genetics)
• Pyrazoles (administration & dosage, adverse effects)
• Pyridines (administration & dosage, adverse effects)
• Pyrroles (administration & dosage, adverse effects)
• Receptor, Platelet-Derived Growth Factor alpha (antagonists & inhibitors, genetics)
• Time Factors
• Triazines (administration & dosage, adverse effects)